Wave movements in the sea and in large inland lakes constitute a potential source of energy that has scarcely been exploited so far. However various suggestions have been made to use the vertical movements of the sea for producing electrical power in a generator. Since a point on the sea surface makes a reciprocating vertical movement it is suitable to use a linear generator to produce the electric power.
WO 03/058055 discloses such a wave power unit where the moving part of the generator, i.e. the part that corresponds to the rotor in a rotating generator and in the present application called translator, reciprocates in relation to the stator of the generator. In that disclosure the stator is anchored in the sea bed. The translator is by flexible connection means, such as a wire, cable or a chain connected to a body floating on the sea.
In such known wave power units the linear generator is encapsulated in a water-tight housing which forms a part of the submerged station. The wire is connected to the translator at the upper end thereof via a rod that passes through a sealed opening in the housing. To connect the wire to the translator via a rod is important for obtaining a good sealing and in order to provide maximal alignment with the translator movements. By the wave movements acting on the floating body, the translator reciprocates up and down since the movement is transferred by the wire and the rod. The rod thus reciprocates correspondingly. This means that the station has to have a sufficient height above the water-tight housing of the generator to allow the reciprocation of the rod. At the upper end there is required some kind of device to adapt the often inclined wire to linear reciprocating movement of the rod. This means that the station requires a considerable building height above the generator. This results in a large height of the complete submerged station such that it will be tower-like.
Since the floating body is connected to the generator by a wire or the like, it has a certain degree of freedom to drift laterally in relation to the submerged station. Lateral forces from the wire will thereby act on the upper end of the submerged station. This results in bending forces on the tower-like construction urging the tower to tilt. The part of the submerged station that is above the generator thereby contributes to increasing the momentum of the tilting forces. The high tilting forces might disturb the performance of the generator. Measures to cope with the tilting momentum are therefore required. The part of the submerged station above the generator also adds to the total construction material that is required.